EUV Lithography

In semiconductor chip production, lithography is a critical manufacturing method utilized to ensure both sufficient quality and high throughput. Optical lithography remains the traditional technique used in the semiconductor industry.

Having reached the technological limits of optical lithography, the semiconductor industry has spent several years identifying potential successor technologies in order to produce even smaller chip features (<100 nm). Next-generation lithography technologies investigated by the semiconductor industry include EUV lithography, x-ray lithography, ion-beam projection lithography, and electron-beam projection lithography. Although EUV lithography has its share of challenges, it has become the choice of the semiconductor industry for the future because it retains the look and feel of the traditional optical lithography process and uses the same basic design tools.

Since the 13.5 nm (~92 eV) wavelength utilized for the EUV lithography process is absorbed in air and requires a high vacuum for transmission, working with this wavelength poses extreme challenges to all production tools. First, the light source has to deliver a narrow band of high EUV power (preferably with high spectral purity) in order to guarantee high throughput. Additionally, all components that move the mask and the wafer with nanometer-range precision must be operated in an ultra-high-vacuum (UHV) environment. Furthermore, the projection optics need to deliver dynamic positioning precision in the Å range and be free of contamination (to the ‘few nanometers’ level) in order to deliver high efficiency.

PI’s Picks

These soft x-ray imaging systems are among the tools of choice for EUV lithography: